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AKB: Biologische Physik

AKB 22: Sensory Biophysics and Signal Transduction

AKB 22.1: Invited Talk

Thursday, March 30, 2006, 14:30–15:00, ZEU 255

Signal processing by clusters of membrane receptors — •T.A.J. Duke and I. Graham — Cavendish Laboratory, JJ Thompson Avenue, Cambridge CB3 0HE, UK

One of the main ways that cells receive information about their environment is through the equilibrium binding of ligand molecules to membrane receptors. Typically, ligand binding causes a change in receptor conformation that triggers a signal transduction cascade in the cell. We investigate the logical repertoire of clusters composed of homologous receptors that can bind more than one type of ligand and show that they are capable of quite sophisticated processing. All of the elementary logical functions can be implemented by appropriate tuning of the ligand binding energies and cooperative interactions between receptors can greatly enhance the sharpness of the response. Receptor clusters can therefore act as digital logical elements whose activity can be abruptly switched from fully inactive to fully active, as the concentrations of the regulators pass threshold values. We discuss a particular instance in which this type of protein logic appears to be used in signal transduction - the chemotaxis receptors of E. coli.